Fixation pin

ABSTRACT

A method including fixing a dental drill template with a fixation pin including a rod and a head attached to the rod. The dental drill template can be fixed by inserting the rod into the drill template or a sleeve provided in the drill template such that a bearing surface of the head bears at least partially on the drill template. The rod has a shape of an essentially circular cylinder and extends from the bearing surface of the head at an essentially right angle. A diameter of the head at the bearing surface is larger than the diameter of the rod.

This is a Divisional of application Ser. No. 16/453,205 filed Jun. 26,2019, which in turn ls a Divisional of application Ser. No. 15/446,945filed Mar. 1, 2017, which in turn is a Divisional of 14/617,327 filedFeb. 9, 2015, which is a Continuation of application Ser. No. 12/627,270filed Nov. 30, 2009, which claims the benefit of EP 08020837 filed Dec.1, 2008. The disclosure of the prior applications is hereby incorporatedby reference herein in its entirety.

The present invention relates to a fixation pin for a dental template,to a set comprising the fixation pin and to its use for fixing a dentaldrill template.

In dentistry it is well known to replace either missing teeth or cariousteeth where the progress of caries is such that they cannot be fixed inanother, less invasive way. Said missing teeth. are usually replaced byan endosseous implant with an artificial supra-structure. While White alot research was done to improve the dental implants itself, tools anddevices which aid in planning the implantation and during the surgicalintervention have long been neglected. However in recent years saidaiding devices became more and more important.

For instance, the drilling of the hole necessary for the endosseous partof the dental implant has been simplified. While at the beginning thedrilling of said hole was purely dependent on the skills of theindividual surgeon there are nowadays drill templates which are adaptedto the anatomy of the individual patient and which serve to achieve aprecise drilling of the holes. The drill template is manufactured aftera preceding check of the anatomy of the patients jaw bone. Such a checkhelps to define the most optimal position of the necessary bore holes.Once this positional information has been obtained and incorporated intothe drill template by means of bore holes, the drill template is used bythe surgeon to provide an optimal guiding of the drill thereby achievingthe desired axis and dimensions of the hole. The drilling of the holesis a crucial step for a successful implantation, since it is hardlypossible to correct wrongly positioned bore holes. Even slightcorrections, e.g. of the drill axis, further diminish jaw bone mass andare thus difficult to correct. Although it is of utmost importance thatdrill templates are kept exactly in position once they have been placedon the jaw or the gum of a patient there are no special means to keepthe drill template in place during its use.

Therefore, the problem of the present invention is to provide means fortemporarily fixing a drill template in its position while the drilltemplate is used.

The problem is solved by a fixation according to claim 1, the setaccording to claim 13 and. the use of the fixation pin according toclaim 14. Preferred embodiments are subject to dependent claims.

A fixation pin for fixing a dental drill template according to thepresent invention has a head which has a bearing surface that isintended to bear at least partially on a drill template or a drillsleeve comprised in the drill template. The fixation pin has further arod that has a shape of an essentially circular cylinder and whichextends from the bearing surface of the head at an essentially rightangle, whereby said rod is intended to be inserted into the drilltemplate or the drill sleeve comprised in the drill template.

The fixation pin provides for a fast and reliable fixation of a drilltemplate and is easy to handle. Since the rod or the fixation pin doesnot have a screw thread there is no screwing requirement. On thecontrary, the essentially cylindrical shape of the rod can be easilyinserted into the drill template or the drill sleeve comprised in thedrill template and ensures a fast and detachable fixation of the drilltemplate. Further, multiple insertion of a rod having a screw thread islikely to damage the bore hole and thus hamper the subsequent insertionof a dental implant such that the implantation is unsuccessful becauseof poor osseointegration of the implant. The fixation pin also serves asa temporary cap of the bore hole and prevents the intrusion of blood,bone debris and other unwanted particles or liquids (e.g. saliva of thepatient). This is particularly advantageous if several holes have to bedrilled. Further, the bearing surface of the head of the fixation pinprovides a physical stop limiting the depth, the fixation pin may beinserted into drill template or the drill sleeve comprised in the drilltemplate, thereby also limiting the depth by which the fixation pinextends into the bore hole that has been drilled into the jaw bone.

In a further embodiment the head of the fixation pin has a shape of anessentially circular cylinder.

In another embodiment the head has a circumventing indentation, saidcircumventing indentation has preferably a concave shape. Thecircumventing indentation provides for a good grip. The good grip avoidsunintentional slipping and/or dropping of the fixation pin by theoperator.

In a further embodiment of the fixation pin the rod has a first portionwhich extends from the bearing surface of the head. The rod has,subsequent to the first portion, a second portion, said second portionhaving a diameter which is smaller than the diameter of the firstportion. The second portion is attached to the first portion of the rod.

The axis of the first portion and the second portion of the rod arepreferably coaxial.

In a further preferred embodiment the first portion of the rod isconnected to the second portion of the rod by an intervening thirdportion which has a conical shape.

In another embodiment the fixation pin is made of one single piece.Being made of one piece the manufacturing of the fixation pin issimplified and its mechanical stability is further improved.

In a further embodiment the fixation pin is made of a material which isselected from the group that consists of hard plastics, stainless steel,titanium and titanium alloys.

In a preferred embodiment the fixation pin is made of titanium or atitanium alloy. Titanium has a very good stability and is biologicallyinert, that is to say, it has an excellent biocompatibility.

In a further embodiment the fixation pin is made of stainless steel. Thematerial stainless steel is most preferred. Stainless steel shows also avery good stability and is biologically inert. Stainless steel isreadily available and is inexpensive.

In another embodiment the fixation pin further comprises an aspirationsecurity. Said aspiration security prevents unwanted aspiration of thefixation pin by the patient. Such an unwanted aspiration may be harmfulfor the patient and cause injury.

In a preferred embodiment the aspiration security is a string that isattached to the head of the fixation pin. For instance, a dental flossmay be bound around the head of the fixation pin, more precisely, aroundthe circumventing indentation.

While the fixation pin is inserted in the drill template or the sleevecomprised in the drill template in a patients mouth, the end of thestring which is opposite to the one attached to the fixation pin may betemporarily fixed outside the mouth of the patient. It may also besimply held by hand.

The present invention also relates to a set that comprises at least onefixation pin according to the present invention. Preferably, the setcomprises more than one fixation pin according to the present invention,whereby at least some of the fixation pins differ in their diameter.Differing in their diameter means that the fixation pins have eitherdifferent diameters in the second portion of the rod and the samediameter in the first portion or they differ in the diameter of thefirst portion, whereas the diameter of the second portion is the same.It is also possible that the fixation pins comprised in the set differin the diameter of the first portion of the rod and the second portionof the rod.

The present invention relates also to the use of a fixation pinaccording to the present invention for fixing a drill template. Thefixation pin provides for a simple and secure fixation of a drilltemplate. Its use is particularly advantageous for fixing drilltemplates which have at least two bore holes.

The fixation pin according to the present invention will be explained inmore detail in the following text with reference to exemplaryembodiments, which are illustrated in the drawings and in which, purelyschematically:

FIG. 1 shows a first embodiment of the fixation pin in a longitudinalsection;

FIG. 2 shows a second embodiment of the fixation pin in a profile view;

FIG. 3 shows the fixation pin according to FIG. 2 in a perspective view;

FIG. 4 shows a further embodiment of the fixation pin in a profile view;and

FIG. 5 shows the fixation pin according to FIG. 4 in a perspective view.

FIG. 1 shows a first embodiment of the fixation pin in a longitudinalsection. The fixation pin 1 has a head 5 which has a bearing surface 10.From the bearing surface 10 a rod 15 extends at an essentially rightangle. The rod 15 has a shape of an essentially circular cylinder andits diameter is constant throughout the length of the rod. The rod 15 isarranged in the centre of the bearing surface 10.

FIG. 2 shows a preferred embodiment of the fixation pin according to thepresent invention. The fixation pin 2 has a head 45 which has a shape ofan essentially circular cylinder. From the bearing surface 40 of thehead 45 extends a rod 55 that also has a shape of an essentiallycircular cylinder. The head 45 and the rod 55 are coaxially arranged andhave a common axis 20. Further, the head 45 has a. circumventingindentation 25 having in a concave shape. The head 45 also carries amark in the form of a coloured, circumventing band 30. Said colouredcircumventing band serves as a colour code for distinguishing differentsets of fixation pins. The colour code may, for instance, refer to thediameter of the bore hole. Since different dental implants require boreholes of different diameter, fixation pins whereby the portion intendedto be inserted into the bore hole meets this requirement, are alsoneeded. The colour code allows for an easy distinction of the differentfixation pins. In addition, the rod carries two height marks 35, 36indicating different heights or distances. These marks provide visiblestop marks that allow the surgeon to insert the fixation pin to acertain depth into the drill template or the drill sleeve comprised inthe drill template and the bore hole. The maximum depth, that a fixationpin can be inserted is limited by the bearing surface of the head of thefixation pin, thereby providing a physical stop.

FIG. 3 shows the fixation pin of FIG. 2 in a perspective view. Thefixation pin 2 which has a head 45 having a circumventing indentation 25of an essentially concave shape. In the concave indentation 25 thecoloured, circumventing band 30 is shown. A rod 55 extends in coaxialdirection from the head 45. Said rod carries height marks 35, 36 ofwhich only one can be seen.

As illustrated in FIGS. 2 and 3, the fixation pin may also comprise an.aspiration security 100. Said aspiration security 100 prevents unwantedaspiration of the fixation pin by the patient. Such an unwantedaspiration may be harmful for the patient and cause injury. Theaspiration security 100 may be a string that is attached to the head ofthe fixation pin, as shown in FIGS. 2 and 3. For instance, a dentalfloss may be bound around the head of the fixation pin, more precisely,around the circumventing indentation

FIG. 4 shows a further embodiment of the fixation pin. The fixation pin3 with a head 65 having a bearing surface 60 from which a rod 95coaxially extends in direction of the common axis 20. The head 65 has acircumventing indentation 75 with a coloured, circumventing band 70. Therod 95 has a first portion 96 extending from the bearing surface 60 anda second portion 97 that has a smaller diameter than the diameter of thefirst portion 96. The first -portion 96 of the rod 95 is connected tothe second portion 97 by an intervening third portion 98 which thirdportion has a conical shape. The height marks 85, 86 are arranged on thefirst portion 96 of the rod 95.

FIG. 5 shows the fixation pin of FIG. 4 in a perspective view. Thefixation pin 3 has a head 65 having a circumventing indentation 75 and acoloured, circumventing band 70. From a bearing surface of the head 65which cannot be seen in this view rod 95 extends at an essentially rightangle. The rod 95 has three different portions 96, 97, and 98. While thefirst portion 96 extends from said bearing surface of the head 65, thesecond portion 97 of the rod 95 is connected to the first portion 96 byan intervening portion 98 which has a conical shape. The second portion97 has a diameter that is smaller than the diameter of the first portion96. The intervening portion 98 has two end faces with differentdiameters. The end face of the intervening portion 98 with the smallerdiameter adjoins the second portion 97 of the rod 95, whereas the endface of the intervening portion 98 having the greater diameter adjoinsthe first portion 96 of the rod 95.

1. A method comprising: fixing a dental drill template with a fixationpin including a rod and a head attached to the rod by inserting the rodinto the drill template or a sleeve provided in the drill template andinto a bore hole formed in a jaw bone such that a bearing surface of thehead bears at least partially on the drill template, wherein: the headof the fixation pin has a shape of an essentially circular cylinder, andextends from a first, free end to a second end in an axial direction ofthe head, the bearing surface is disposed at the second end of the head,and an upper surface that is continuous is disposed. at the first, freeend of the head opposite to the bearing surface, a peripheralindentation is formed around an outer circumferential surface of thehead between the bearing surface and the upper surface of the head, therod has a. shape of an essentially circular cylinder, and extends fromthe bearing. surface of the head at an essentially right angle, the rodhas a length that extends between a first rod end at the bearing surfaceof the head and a second, free rod end, a diameter of the rod isconstant along the length of the rod between. the first rod end and thesecond, free rod end, and a diameter of the head at the bearing surfaceis larger than the diameter of the rod.
 2. The method according to claim1, wherein the peripheral indentation has a concave shape.
 3. o Themethod according to claim 1, wherein the fixation pin is made of onesingle piece.
 4. The method according to claim 1, wherein the fixationpin is made of a material selected from the group consisting of hardplastics, stainless steel, titanium, and titanium alloys.
 5. The methodaccording to claim 4, wherein the fixation pin is made of a materialselected from the group consisting of titanium and titanium alloys. 6.The method according to claim 4, wherein the fixation pin is made ofstainless steel.
 7. The method according to claim 1, further comprisingan aspiration security member.
 8. The method according to claim 7,wherein the aspiration security member is a string attached to the headof the fixation pin.
 9. The method according to claim 1, wherein thediameter of the rod is configured to correspond to a diameter of thebore hole.
 10. The method according to claim 9, wherein the headincludes a mark indicating the diameter of the bore hole thatcorresponds to the diameter of the rod.
 11. The method according toclaim 1, wherein the drill template is fixed with two or more of thefixation pins.
 12. The method according to claim 11, wherein at leastone of the two or more fixation pins has a diameter different fromanother one of the two or more fixation pins.
 13. The method accordingto claim 1, wherein the fixation pin also serves as a temporary cap ofthe bore hole.
 14. The method according to claim 1, wherein theperipheral indentation connects the first, free end and the second endof the head and forms in the axial direction of the head a continuousconcave-shaped curve that extends from the first, free end of the headto the second end of the head.
 15. The method according to claim 1,wherein the rod has a cylindrical outer surface from the first rod endto the second rod end.
 16. The method according to claim 1, wherein thesecond, free rod end is a rounded free end.